ABCB1 rs3213619: Understanding Pharmacogenomic Research
The rs3213619 variant is a single nucleotide polymorphism located within the ABCB1 gene, which encodes a protein responsible for transporting various substances across cell membranes. Researchers study this variant to determine if it influences how the body processes immunosuppressive medications like tacrolimus and cyclosporine in transplant patients.
What each genotype means
Typical transporter activity
This genotype represents the most common form of the ABCB1 gene at this location. Research into the impact of this specific variant on drug metabolism is limited and often inconsistent, so it is not currently used to guide clinical dosing. Please discuss any medication concerns or side effects with your healthcare provider.
This is the most common genotype observed in most global populations.
Heterozygous genotype
You carry one copy of the common allele and one copy of the variant allele at this position. Studies investigating whether this variant influences the processing of immunosuppressive drugs have yielded mixed or inconclusive results. Because the evidence is limited, this genotype does not currently change standard clinical recommendations; consult your pharmacist or doctor regarding your specific treatment plan.
This genotype is found at varying frequencies across different ancestral groups.
Variant genotype
You carry two copies of the variant allele at this position. While some research has explored the role of ABCB1 variants in drug transport, the evidence linking this specific variant to clinical outcomes remains limited and inconsistent. This genotype is not currently used to adjust medication dosages, so please continue to follow your clinician's guidance for your therapy.
This genotype is less common than the homozygous CC genotype in most studied populations.
What is the rs3213619 Variant?
A single nucleotide polymorphism (SNP), such as rs3213619, represents a variation at a single position in the DNA sequence. In the context of the ABCB1 gene, scientists investigate whether these small changes in the genetic code lead to functional differences in the proteins produced by the body. The rs3213619 variant is specifically categorized under pharmacogenomics, a field that examines how an individual's genetic makeup affects their response to drugs. Because the ABCB1 gene is involved in the transport of many compounds, researchers look for associations between this specific SNP and the way medications are absorbed, distributed, or cleared from the system. It is important to note that identifying a variant does not automatically mean it causes a significant change in drug response; rather, it serves as a marker for ongoing scientific investigation into biological variability.
The Role of the ABCB1 Gene
The ABCB1 gene, also known as the multidrug resistance protein 1 (MDR1) gene, provides instructions for making a protein called P-glycoprotein. This protein acts as a biological pump, moving various molecules, including toxins and drugs, out of cells. By pumping these substances out, P-glycoprotein plays a critical role in protecting tissues from harmful compounds and influencing the concentration of therapeutic drugs in the bloodstream. In clinical settings, the activity of this pump can determine how much of a medication reaches its target site. Because immunosuppressive drugs like tacrolimus and cyclosporine are substrates for this pump, variations in the ABCB1 gene have been hypothesized to potentially alter the effectiveness or side-effect profiles of these treatments. Understanding this gene is essential for researchers aiming to optimize drug dosing, particularly in patients who have undergone organ transplantation and require precise medication management.
Current Research and Evidence Strength
The evidence linking rs3213619 to specific clinical outcomes remains limited. While many studies have explored the impact of various ABCB1 polymorphisms on the pharmacokinetics of immunosuppressive drugs, the results have often been inconsistent or inconclusive. Some research suggests that while certain ABCB1 variants might show modest effects in specific cohorts, they often do not reach the level of clinical significance seen with other genes, such as CYP3A5. Systematic reviews have noted that methodological differences between studies can make it difficult to draw definitive conclusions about the impact of rs3213619. Consequently, current medical guidelines do not typically recommend routine testing for this specific variant to guide dosing. The scientific community continues to evaluate whether this SNP, either alone or in combination with other genetic and clinical factors, provides meaningful predictive value for patient care.
What This Information Means for You
If you have received information about your rs3213619 genotype, it is important to understand that this data is primarily used for research purposes and does not currently dictate standard clinical practice. Genetic associations are complex, and a single variant rarely determines how a person will respond to a medication on its own. Many factors, including age, organ function, other medications, and additional genetic markers, play a much larger role in drug metabolism. You should never use genetic information to make decisions about your medication, such as changing your dose or stopping a treatment. If you are concerned about how your body is processing a prescribed drug, the most appropriate step is to discuss your questions with your transplant team, clinician, or pharmacist. They are best equipped to interpret your clinical situation and ensure your treatment plan is safe and effective.
How common is this variant?
There is no widely recorded population frequency data for rs3213619 in major public databases, and its prevalence is considered to be under investigation.
Frequently asked questions
Does my rs3213619 genotype mean I need a different dose of my medication?
No. Current research does not support using the rs3213619 genotype to adjust medication dosages. Always consult your doctor before making any changes to your prescribed treatment.
Is rs3213619 the same as other ABCB1 variants?
No, rs3213619 is a specific location in the ABCB1 gene. Other variants, such as rs1045642, are studied separately and may have different associations with drug metabolism.
Why is the evidence for this variant considered limited?
Evidence is considered limited because studies have produced inconsistent results, and many findings have not been replicated in large, diverse clinical populations. This makes it difficult to establish a reliable link between the variant and clinical outcomes.
Should I get tested for this variant?
Routine testing for rs3213619 is not currently recommended by clinical guidelines. Genetic testing for drug response should only be performed if ordered by a healthcare provider for a specific clinical reason.
Sources & further reading
Educational information only, last refreshed 9/29/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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Synonymous variant (c.3435C>T) in ABCB1 linked to altered P-glycoprotein expression and multi-drug transporter pharmacokinetics.
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A variant associated with potential differences in drug absorption and clinical outcomes in patients undergoing specific pharmacological therapies.
This SNP is linked to variations in the pharmacokinetics of drugs that are substrates for the ABCB1 transporter protein.